Serbs Complying on Pullout, U.N. Says; Air Strikes Averted : Balkans: Some heavy arms remain, but weather may have prevented removal. NATO and U.S. also agree enough progress has been made to forestall military action.

A NATO deadline to Serbian gunners besieging the Bosnian capital of Sarajevo expired in uneasy silence early today, with some heavy weapons still aimed at the city but enough gone to rule out immediate air strikes.

U.N. officials authorized to call for NATO air strikes said some Serbian guns were not surrendered or removed from a 12-mile zone around Sarajevo after the deadline of 1 a.m. today local time (4 p.m. Sunday Pacific time). They said that in some cases wintry weather prevented the weapons’ removal.

But officials from the United Nations, NATO and the Clinton Administration said enough progress had been made to avert air strikes for the time being.

“I am satisfied we have achieved effective compliance. I have decided that it is not necessary at this stage for me to request NATO to use air power,” said Yasushi Akashi, the senior U.N. official in Bosnia-Herzegovina, in a statement released at his Zagreb, Croatia, headquarters and at NATO headquarters in Brussels.

He said Jeremy Boorda, the four-star American admiral who commands NATO forces in Naples, is “exactly of the same opinion as myself.”

President Clinton said air strikes are unnecessary “at this time.”

But, in a statement read by Press Secretary Dee Dee Myers, he said: “Despite the significant events of the day, we must remain vigilant.

“All parties should be aware that the ultimatum stands. The deadline has not been extended. Any heavy weapons in the exclusion zone not under U.N. control are, and will remain, subject to air strikes.”

NATO Secretary General Manfred Woerner said early today that he had agreed in telephone calls with Clinton to keep the threat of air strikes intact in case weapons are moved back toward Sarajevo or the city is attacked.

The acknowledged violations of NATO’s 10-day ultimatum for all heavy weaponry to be removed or disabled prompted Bosnian President Alija Izetbegovic to appeal for immediate Western intervention to punish the Serbs.

“They knew very well of the weather conditions, and they did nothing for seven days,” the Muslim president wrote in a message to Woerner. “They are guilty for not doing this on time. . . . I think that heavy weaponry that remains tonight after midnight should be a target for NATO air strikes.”

The Bosnian Serb forces that have shelled the city for nearly two years did not respond at first to NATO’s demand to surrender or remove their heavy weapons from the exclusion zone. But the ultimatum did halt shelling that has claimed 10,000 lives in the city in the past 22 months.

And by late last week, Serbian weapons began withdrawing from hillsides around the city after Russia promised to add troops to the peacekeeping force there.

The ultimatum was set after a shell killed 68 people in a Sarajevo market on Feb. 5. It was the worst single massacre of the Bosnian civil war, shocking the world and forcing the United States and Russia to take a leading role in the search for an end to the conflict.

In Naples, Italy, lights burned toward dawn today at North Atlantic Treaty Organization headquarters. Any decision to attack remaining emplacements would come only after daylight examination of them and political consultations among NATO partners, senior officers said.

“We’ve been ready, and we remain ready,” said NATO spokesman James Mitchell, a U.S. Navy captain.

Lt. Gen. Michael Rose, the British commander of U.N. forces in Bosnia who would summon any strikes, said late Sunday that he was “cautiously optimistic” that they would not be needed.

“I hope we will not have to use air strikes tomorrow,” Rose said. “If there are breaches of the cease-fire tomorrow, I will have no hesitation of calling down air strikes. . . . But I don’t expect that to be the case.”

Defense Secretary William J. Perry, en route back to Washington from a defense ministers’ meeting at Aviano Air Base in northern Italy, called the decision to hold off on air strikes “really great news” and “an enormous relief,” but he said U.N. forces would have to continue to watch the situation.

“This is very good news, but it’s not over yet,” he said. “They are going to continue to watch, and if we find more artillery pieces, if artillery pieces move in the future, then we have to reconsider this.”

U.S. Gen. John M. Shalikashvili, chairman of the Joint Chiefs of Staff, who traveled to Italy with Perry, said it could be several days before the allies know for sure whether the Serbs have fully complied.

Perry said the Serbian surrender of artillery went slowly and painfully right up until the final hours on Sunday, with U.N. forces ultimately visiting each of the Serbian weapons sites individually to take possession of guns, tanks, mortars and rockets.

He said NATO reconnaissance planes will continue flying over the Sarajevo area, with a view toward confirming that the Serbs have surrendered their weapons as ordered. Reconnaissance efforts were hampered over the weekend by bad weather, but analysts say the weather now is improving.

A senior official returning to Washington with Perry told reporters that the United States had offered to send sophisticated TPQ-36 and TPQ-37 artillery-locating radar to help pinpoint Serbian weapons but had declined to send ground troops to operate them and was trying to train British or French troops to take those posts.

Britain and France already have contributed seven units of French-built Cymbeline mortar-locating radar, complete with the necessary ground crews.

On Sunday, some Bosnian Serb gunmen manning artillery emplacements under the control of nearby U.N. troops brushed off the potential risks of failing to comply with the NATO ultimatum.

“We’re not afraid of the West,” said Zoran Pijevic, 28. “In the event of (NATO) intervention, the Serbs and the Russians will see to it that Vienna doesn’t exist anymore.”

Much of the Serb rebel resentment driving the war in Bosnia-Herzegovina stems from a sense of historic injustice at the hands of foreign powers such as nonaligned Austria, which occupied the republic until World War I.

Pijevic’s half brother, 24-year-old Goran, boasted that the Russian U.N. troops had come to shore up the Serbian side and that their presence meant NATO had given up intentions to target rebel installations.

Williams reported from Sarajevo and Montalbano from Naples. Times staff writers Art Pine in Aviano, Italy, and Carey Goldberg in Moscow contributed to this report.